This invention relates to automatic analytical instruments. In particular, the invention is directed to an injection cell for injecting fluid samples into the instrument for analysis.
Different analyzers are available for automatic clinical chemistry analysis. The analyzers use different types of analytical procedures to obtain desirable attributes and advantages.
One particular kind uses a plurality of individual analysis modules having open reaction or sample cups. An automated sample probe withdraws a sample volume from samples in the sample cups carried on a carousel and distributes the sample fluid to analysis modules in accordance with tests selected by an instrument operator.
Another kind of analyzer uses a flow cell through which the sample and a diluent flows to determine electrolytes in the sample. This analyzer also uses a sample pick-up probe to extend into the sample cup to aspirate the sample into the probe. Thereafter, the sample is ejected or dispensed from the probe into an injection cell.
Drawbacks arise with existing designs of the injection cell and related probe. Periodic washing of the probe is required so that contamination from one sample to another sample does not occur. For this purpose, different washing stations are used into which the probe is periodically submitted. The washing station would be used between each test. The disadvantage of this is that a specific time period is necessary to effect the washing. This increases the time cycle necessary for analyzing multiple samples. Additionally, separate mechanisms and facilities need to be provided for the washing and the components for this often require pump means. This is relatively expensive and a drawback of existing injection cells.
The present invention seeks to overcome the drawbacks in the prior art.